Lamp unit and lighting fixture

ABSTRACT

According to one embodiment, a lamp unit includes a light-emitting module, a housing, a lighting circuit, and a heat conductive sheet. The light-emitting module includes a light emitting portion having a semiconductor light-emitting element formed thereon. The housing includes a case opening in the direction of irradiation of light, and a base on a side of the case opposite from the direction of irradiation of the light. The light-emitting module is mounted on a surface of the base on the case side. A base surface is formed on an outer surface of the base on the side opposite from the case side, and a depressed portion is formed on the base surface. The lighting circuit is accommodated in the housing. The heat conductive sheet allows resilient deformation, and is disposed in the depressed portion.

INCORPORATION BY REFERENCE

The present invention claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2010-258056 filed on Nov. 18, 2010. The contentof the application is incorporated herein by reference in its entirety.

FIELD

An embodiment of the present invention relates to a lamp unit using asemiconductor light-emitting element and a lighting fixture using thislamp unit.

BACKGROUND

In the related art, there are flat-type lamp units using a GX53-typebase. The lamp unit of this type includes a metallic base member, and alight-emitting module having a semiconductor light-emitting elementmounted on one surface of the base member, a transmissive cover mountedso as to cover the light-emitting module, the GX53-type base having apair of lamp pins projected therefrom and mounted on the other surfaceof the base member, and a lighting circuit accommodated in the base.

This lamp unit is configured to be mounted by pressing the base to asocket of the lighting fixture, and then rotating the same by apredetermined angle.

In the case of such a lamp unit, when increasing a light output usingthe light-emitting module using large making power, the amount of heatgeneration of the light-emitting module is increased correspondingly.Therefore, an improvement of radiating performance from the lamp unit isnecessary.

In order to improve the radiating performance from the lamp unit, it isconceivable to bring the base of the lamp unit into contact with thelighting fixture side to achieve efficient heat conduction with the lampunit mounted on the lighting fixture. At this time, by interposing theheat conductive sheet between the base of the lamp unit and the lightingfixture, adhesiveness is improved and the heat conduction efficiency canfurther be improved.

When the heat conductive sheet is used, the base of the lamp unit ismounted by pressing toward the lighting fixture via the heat conductivesheet. However, if the pressing force is too strong, the heat conductivesheet cannot move easily from the pressed position on the side of thelighting fixture and hence mounting of the lighting fixture by rotatingthe lamp unit may become difficult, or the heat conductive sheet maybecome damaged.

It is an object of the invention to provide a lamp unit and a lightingfixture in which radiating performance is secured and lowering ofmounting and demounting operability or damage of the heat conductivesheet can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a lamp unit according to a firstembodiment;

FIG. 2 is an exploded perspective view of the lamp unit according to thefirst embodiment;

FIG. 3 is a perspective view of one surface of the lamp unit accordingto the first embodiment;

FIG. 4 is a perspective view of the other surface of the lamp unitaccording to the first embodiment;

FIG. 5( a) is a cross-sectional view of part of a heat conductive sheetof the lamp unit according to the first embodiment, before the lamp unitis mounted on a lighting fixture;

FIG. 5( b) is a cross-sectional view of the part of the heat conductivesheet of the lamp unit according to the first embodiment with the lampunit mounted on the lighting fixture;

FIG. 6 is a cross-sectional view of the lighting fixture using the lampunit according to the first embodiment;

FIG. 7 is an exploded perspective view of the lamp unit according to thefirst embodiment;

FIG. 8 is a perspective view of the other surface of a lamp unitaccording to a second embodiment;

FIG. 9 is a cross-sectional view showing part of the lamp unit accordingto the second embodiment;

FIG. 10 is a perspective view of one surface of a lamp unit according toa third embodiment; and

FIG. 11 is a perspective view of a radiating member of a lightingfixture according to a fourth embodiment.

DETAILED DESCRIPTION

A lamp unit according to an embodiment includes a light-emitting module,a housing, a lighting circuit, and a heat conductive sheet. Thelight-emitting module includes a semiconductor light-emitting element.The housing includes a case opening in the direction of irradiation oflight, and a base on a side of the case opposite from the direction ofirradiation of the light. The light-emitting module is mounted on thebase. A base surface is formed on an outer surface of the base on theside opposite from the case side, and a depressed portion is formed onthe base surface. The lighting circuit is accommodated in the housing.The heat conductive sheet allows resilient deformation, and is disposedin the depressed portion.

By mounting the base of the lamp unit by pressing to the lightingfixture side via the heat conductive sheet, heat conduction from thebase toward the lighting fixture is improved, and hence the radiatingperformance can be secured. Furthermore, when mounting the base of thelamp unit by pressing the same against the lighting fixture side via theheat conductive sheet, the heat conductive sheet comes into abutmentwith the lighting fixture side, is resiliently deformed, and is pressedagainst the interior of the depressed portion first. Then, the basecomes into abutment with the lighting fixture side and restricts furtherresilient deformation of the heat conductive sheet, so that increase ofthe pressing force that the heat conductive sheet is pressed against thelighting fixture side is restricted. Therefore, it is expected thatexcessive deformation of the heat conductive sheet is prevented, themounting operation on the basis of the rotation of the lamp unit withrespect to the lighting fixture is facilitated, and damage of the heatconductive sheet is prevented.

Referring now to FIG. 1 to FIG. 7, a first embodiment will be described.

As shown in FIG. 6 and FIG. 7, a lighting fixture 11 is anembedding-type lighting fixture such as a downlight, and is installed ina state of being embedded into a circular embedding hole 13 provided ina portion to be installed 12 such as a ceiling panel.

The lighting fixture 11 includes a fixture body 15, a socket 16 and aradiating member 17 integrally fixed to the fixture body 15, and aflat-type lamp unit 18 to be demountably mounted to the socket 16.

In the following description, with the lighting fixture 11 installedhorizontally and the flat-type lamp unit 18 mounted on the lightingfixture 11 horizontally, a direction of irradiation of light, which isone side of the lamp unit 18, is defined as “lower” (for example, lowersurface, lower side, lower portion, lower end, etc.), a directionopposite from the irradiation of light, which is the other side, isdefined as “upper” (for example, upper surface, upper side, upperportion, upper end, etc.).

First of all, as shown in FIG. 1 to FIG. 5, the lamp unit 18 includes aflat-shaped cylindrical housing 21, a heat conductive sheet 22 mountedon an upper surface of the housing 21, a light-emitting module 23, alight control unit 24, and a lighting circuit 25 accommodated in thehousing 21, and a glove 26 mounted on a lower surface of the housing 21.

The housing 21 includes a cylindrical case 28 and a cylindrical basemember 29 to be mounted on an upper surface of the case 28. A base 30 isconfigured with an upper surface side of the case 28 and the base member29 projecting from the upper surface of the case 28.

The case 28 is formed, for example, of a synthetic resin havinginsulating properties and includes a flat panel portion 31 on the uppersurface and a peripheral surface portion 32 projecting downward from aperipheral portion of the flat panel portion 31. The flat panel portion31 is formed with a through-hole 33 at a center thereof, a plurality ofmounting holes 34 radially outside of the through-hole 33, and aplurality of insertion holes 35 on the radially outside of the mountingholes 34. A patterned indented portion 32 a is formed on an outerperipheral surface of the peripheral surface portion 32 on the side ofan upper portion thereof for increasing the surface area.

The base member 29 is formed of a material selected from a group ofmetals such as aluminum die-cast, ceramics, or resins superior in heatconductivity, and includes an end surface 36 as a base surface on anupper surface (an outer surface opposite from the side of the case), anda peripheral surface portion 37 projecting downward from the peripheryof the end surface 36. Formed inside the peripheral surface portion 37are a plurality of bosses 39 which allow a plurality of screws 38 usedfor fixing the case 28 with the base member 29 to be screwed therein viathe plurality of the mounting holes 34 of the case 28.

Formed integrally with a lower surface of the end surface 36 (thesurface on the side of the case) at the center thereof is a heatconducting portion 40 projecting toward the case 28, the heat conductingportion 40 is formed with a flat-shaped mounting surface 41 for mountingthe light-emitting module 23 on a lower surface thereof, and themounting surface 41 is formed with a plurality of mounting holes 42. Theheat conducting portion 40 is formed to be thicker than other portion ofthe base member 29. An annular restricting portion 43 is formed on aperipheral portion of the end surface 36 so as to project therefrom anda depressed portion 30 a for positioning and mounting the heatconductive sheet 22 is formed inside the restricting portion 43.

Formed on the peripheral surface portion 37 are a plurality of keygrooves 44. Each of the key grooves 44 is formed into a substantiallyL-shape including a vertical groove 44 a formed along the verticaldirection so as to continue to the upper surface of the base member 29and a lateral groove 44 b formed on a lower portion of the peripheralsurface portion 37 in the circumferential direction of the peripheralsurface portion 37. In addition, the peripheral surface portion 37 isformed with a plurality of keys 45 at positions between the adjacent keygrooves 44 and lower than the position of the end surface 36 so as toproject therefrom as socket mounting portions. Although three each ofthe key grooves 44 and the keys 45 are provided in this embodiment, atleast two each of them are necessary and four each or more of those mayalso be provided.

The heat conductive sheet 22 is configured to be brought into intimatecontact with the radiating member 17 if the lamp unit 18 is mounted onthe lighting fixture 11 and conduct heat from the lamp unit 18 to theradiating member 17 efficiently. As shown in FIG. 5, the heat conductivesheet 22 is formed into a disk shape and includes a silicone sheet 47having resiliency and adhered to the end surface 36 inside therestricting portion 43 of the base member 29 and a metal foil 48 such asaluminum, tin, or zinc to be adhered to an upper surface of the siliconesheet 47. A frictional resistance of the surface of the metal foil 48 issmaller than that of the silicone sheet 47.

As shown in FIG. 5( a), if the lamp unit 18 is not mounted on thelighting fixture 11 and no pressure is applied on the heat conductivesheet 22, the projecting dimension of the heat conductive sheet 22 fromthe end surface 36 of the base member 29 is larger than the height ofthe restricting portion 43. As shown in FIG. 5( b), if the lamp unit 18is mounted on the lighting fixture 11, the heat conductive sheet 22 ispressed against the radiating member 17, and a pressure is applied tothe heat conductive sheet 22, the heat conductive sheet 22 (the siliconesheet 47) can be compressed within a range of resilient deformationthereof until the projecting dimension of the heat conductive sheet 22from the end surface 36 of the base member 29 becomes the same as theheight of the restricting portion 43.

The light-emitting module 23 includes a substrate 51, a light-emittingportion 52 formed on a lower surface of the substrate 51, a connector 53mounted on the lower surface of the substrate 51, a frame-shaped holder54 configured to hold the periphery of the substrate 51, and a heatconductive sheet 55 interposed between the substrate 51 and the mountingsurface 41 of the heat conducting portion 40 of the base member 29 wherethe substrate 51 is to be mounted.

The substrate 51 is formed of a material such as a metal or ceramicssuperior in heat conductivity into a flat panel shape.

The light-emitting portion 52 employs a semiconductor light-emittingelement 52 a such as an LED element or an EL element as a light source.In this embodiment, LED elements are employed as the semiconductorlight-emitting element 52 a, and a COB (Chip On Board) system in which aplurality of the LED elements are mounted on a substrate is employed. Inother words, the plurality of the LED elements are mounted on thesubstrate, and the plurality of the LED elements are electricallyconnected in series by wire bonding, and the plurality of the LEDelements are integrally covered and sealed with a fluorescent materiallayer, which is a transparent resin such as a silicone resin having afluorescent material mixed thereto. For example, LED elements emittingblue light are employed as the LED elements, and the fluorescentmaterial which emits yellow light by being pumped by part of the bluelight from the LED elements is mixed to the fluorescent material layer.Therefore, the light-emitting portion 52 is composed of the LED elementsand the fluorescent material layer, and the surface of the fluorescentmaterial layer, which is the surface of the light-emitting portion 52serves as a light-emitting surface, and white illuminating light isradiated from the light-emitting surface. As the light-emitting portion,a system of mounting a plurality of SMD (Surface Mount Device) packageswith connecting terminals having the LED elements mounted thereon on thesubstrate may be employed.

The connector 53 is electrically connected to the LED elements.

The holder 54 holds the substrate 51, and is fixed in a state ofsandwiching the heat conductive sheet 55 and the substrate 51 withrespect to the heat conducting portion 40 of the base member 29 with aplurality of screws 56 screwed into a plurality of the mounting holes 42on the heat conducting portion 40 of the base member 29. Accordingly,the substrate 51 is brought into intimate contact with the heatconducting portion 40 of the base member 29 via the heat conductivesheet 55, so that satisfactory heat conductivity from the substrate 51to the base member 29 is ensured.

The heat conductive sheet 55 may be a metal foil such as aluminum, tin,or zinc instead of the silicone sheet. By using the metal foil,deterioration due to heat is less serious than the silicone sheet, sothat the heat conducting performance can be maintained for a long term.

The light control unit 24 is formed of a cylindrical reflecting member.The light control unit 24 is formed of, for example, a synthetic resinhaving insulating properties, includes a cylindrical light guide portion59 broadened step by step or continuously from an upper end side towarda lower end side, and an annular cover portion 60 formed at a lower endof the light guide portion 59 so as to cover the periphery of a lowersurface of the case 28. Formed on an inner surface of the light guideportion 59 and a lower surface of the cover portion 60 is a reflectingsurface 61 having a high optical reflectance in white or having mirrorsurface. An upper end of the light guide portion 59 projects into thebase member 29 through the through-hole 33 of the case 28, and is heldby the holder 54 of the light-emitting module 23 in abutment. Therefore,the light-emitting module 23 and the lighting circuit 25 are separatedby the light control unit 24. The light control unit 24 may be a lens,or may be a combination of a reflecting member and a lens.

The lighting circuit 25 configures a power circuit configured to rectifyand smooth a commercial power supply voltage and output aconstant-current DC power, and includes a lighting circuit board 64 andlighting circuit components 65, which are a plurality of electroniccomponents mounted on the lighting circuit board 64. The lightingcircuit 25 is accommodated and mounted in the case 28 formed of aninsulating material.

The lighting circuit board 64 is formed into an annular shape having acircular opening 66 for allowing penetration of the light control unit24 at a center portion thereof. A lower surface of the lighting circuitboard 64 is a mounting surface 64 a for mounting discrete componentshaving a lead wire from among the lighting circuit components 65, and anupper surface is a wiring pattern surface 64 b formed with a wiringpattern for connecting the lead wires of the discrete components andmounting the surface mounting components from among lighting circuitcomponents.

Among the lighting circuit components 65 to be mounted on the mountingsurface 64 a of the lighting circuit board 64, at least one, preferablyall, of large components having a large projecting height from thelighting circuit board 64, heat generating components with highcalorific value, and components having a low tolerance for heat such asan electrolytic capacitor are mounted at outer positions of the lightingcircuit board 64. The components having a low tolerance for heat such asthe electrolytic capacitor are mounted at positions away from the lightguide portion 59 of the light control unit 24 on the lighting circuitboard 64. The annular lighting circuit board 64 includes componentswhich may generate a noise such as a switching element mounted atpositions away and opposite from the position of the power supply inputportion in terms of the circumferential direction.

The lighting circuit board 64 is arranged on an upper side in the case28 in a state in which the wiring pattern surface 64 b opposes an innersurface of the flat panel portion 31 of the case 28 in parallel. Thelighting circuit components 65 mounted on the mounting surface 64 a ofthe lighting circuit board 64 are arranged between the peripheralsurface portion 32 of the case 28 and the light guide portion 59 and thecover portion 60 of the light control unit 24.

Provided so as to project vertically from a peripheral portion, of thewiring pattern surface 64 b of the lighting circuit board 64 are aplurality of lamp pins 67 electrically connected to the wiring pattern.The plurality of the lamp pins 67 include two lamp pins 67 for the powersupply, two lamp pins 67 for light control signals, and one lamp pin 67for grounding. These lamp pins 67 are press-fitted into the respectiveinsertion holes 35 of the case 28 and project vertically upward of thecase 28. In other words, the plurality of the lamp pins 67 projectvertically from an upper surface of the base 30.

For reference sake, at least two lamp pins 67 for the power supply areessential and other lamp pins 67 do not necessarily have to be provided.Alternatively, the lamp pins 67 may not be provided on the lightingcircuit board 64 and dummy pins to be press-fitted and fixed into theinsertion holes 35 of the case 28 may be provided.

Connected to an output terminal of a DC power supply of the lightingcircuit 25 is wiring with a connector to be connected to the connector53 of the light-emitting module 23.

The glove 26 is formed, for example, of a transmissive synthetic resinor glass, and is fitted into a lower portion of the peripheral surfaceportion 32 so as to cover the lower surface of the case 28, and ismounted on the case 28 with a plurality of claws 69 provided on aperipheral portion of the glove 26 being locked on the peripheralsurface portion 32. In the peripheral portion of a lower surface of theglove 26, finger placing portions 70 including a plurality ofprojections are provided on a plurality of positions, for example, twopositions, on a circumference of the glove 26 so as to be projectedtherefrom, and a triangle mark 71 indicating a mounting position withrespect to the lighting fixture 11 is formed at one position. It is alsopossible to form a Fresnel lens which controls direction of irradiationof light from the light-emitting portion 52 through the glove 26, thatis, distribution of light, on an inner surface of the glove 26 opposingthe light-emitting portion 52 of the light-emitting module 23.

In the lamp unit 18 configured as described above, the lighting circuit25 is arranged in the case 28, the light-emitting module 23 is arrangedin the base member 29, which is a position on the side of the base 30with respect to the position of the lighting circuit 25 in the case 28,and the light-emitting module 23 is mounted to the base member 29 bybeing thermally bonded. In addition, the light-emitting module 23 isarranged at an upper position closer to the end surface 36 of the basemember 29 with respect to the position of the upper surface of the case28. The light-emitting module 23 and the lighting circuit 25 areseparated by the light control unit 24. The light guide portion 59 ofthe light control unit 24 is arranged in the opening 66 of the lightingcircuit board 64 and in the through-hole 33 of the case 28, and thecover portion 60 of the light control unit 24 covers and shields thelighting circuit 25 in the case 28.

The input power (consumed power) and the total luminous flux of thelight-emitting module 23 in the lamp unit 18 in this embodiment are 20to 25 W and 1100 to 1650 lm, respectively.

Subsequently, as shown in FIG. 6 and FIG. 7, the fixture body 15 of thelighting fixture 11 is used also as a reflective member, and is formedso as to open downward. Formed at a lower end of the fixture body 15 isa flange portion 81 projecting sideward, and a fitting hole 82 is formedon an upper surface of the fixture body 15. Provided on an innerperipheral surface of the fixture body 15 at one position is a trianglemark 83 indicating a mounting position of the lamp unit 18.

The socket 16 includes a socket body 85 formed of a synthetic resinhaving insulating properties, for example, into an annular shape and aplurality of terminals, not shown, arranged in the socket body 85.

Formed at a center of the socket body 85 is an insertion opening 86 forallowing insertion of the base member 29 of the lamp unit 18. On a lowersurface of the socket body 85, a plurality of connecting grooves 87,formed into an elongated hole, for allowing insertion of the respectivelamp pins 67 of the lamp unit 18, are arranged in the circumferentialdirection.

Formed on an inner peripheral surface of the socket body 85 are aplurality of key grooves 88. Each of the key grooves 88 is formed into asubstantially L-shape including a vertical groove 88 a formed along thevertical direction and a lateral groove 88 b formed on the side of anupper portion of the socket body 85 in the circumferential direction. Inaddition, formed on the inner peripheral surface of the socket body 85between the plurality of the key grooves 88 so as to project therefromare a plurality of keys 89. The key grooves 88 and the keys 89, and thekeys 45 and the key grooves 44 of the lamp unit 18 correspond to eachother respectively, so that the lamp unit 18 can be demountably mountedto the socket 16.

The respective terminals are arranged on an upper side of the respectiveconnecting grooves 87, the lamp unit 18 is mounted in the socket 16, andthe respective lamp pins 67 inserted into the respective connectinggrooves 87 are electrically connected.

The radiating member 17 is formed of a material selected from a group ofmetals such as aluminum die-cast, ceramics, or resin superior in heatradiation. The radiating member 17 includes a cylindrical base portion91 and a plurality of radiating fins 92 projecting radially from theperiphery of the base portion 91.

Formed at a center portion of a lower surface of the base portion 91 isa circular projecting portion 93 closing the lower surface of the baseportion 91, and a flat contact surface 94 is formed on a lower surfaceof the projecting portion 93.

A plurality of mounting portions 95 are formed on the periphery of thebase portion 91 of the radiating member 17, and mounting springs 96 formounting the lighting fixture 11 to the portion to be installed 12 aremounted to the mounting portions 95.

Mounted on an upper surface of the radiating member 17 are a mountingplate 99 having a terminal base 97 for the power supply and a terminalbase 98 for the light control signals mounted thereon.

The lighting fixture 11 is fixed with screws with the fitting hole 82 ofthe fixture body 15 fitted around the projecting portion 93 of theradiating member 17, and the fixture body 15 sandwiched between theradiating member 17 and the socket 16. The contact surface 94 of theradiating member 17 is arranged so as to be exposed from an uppersurface of the insertion opening 86 of the socket 16.

Subsequently, mounting of the lamp unit 18 on the lighting fixture 11will be described.

The lamp unit 18 is inserted from an opening on the lower surface of thefixture body 15, the mark 71 indicated on the lamp unit 18 is alignedwith the mark 83 indicated on an inner surface of the fixture body 15,and the lamp unit 18 is pushed upward so as to be inserted into thesocket 16.

Accordingly, the base member 29 of the lamp unit 18 is fitted into theinsertion opening 86 of the socket 16 first, then the respective keys 89of the socket 16 enter the vertical grooves 44 a of the respective keygrooves 44 of the base member 29 and the respective keys 45 of the basemember 29 enter the vertical grooves 88 a of the respective key grooves88 of the socket 16, the respective lamp pins 67 of the lamp unit 18 areinserted into the corresponding connecting grooves 87 of the socket 16respectively, and then the upper surface of the base member 29 comesinto abutment with the contact surface 94 of the radiating member 17 viathe heat conductive sheet 22. At this time, since the heat conductivesheet 22 projects from the restricting portion 43 of the base member 29,firstly, the heat conductive sheet 22 comes into abutment with thecontact surface 94 of the radiating member 17 and hence is compressed,and then the restricting portion 43 of the base member 29 comes intoabutment with the contact surface 94 of the radiating member 17.

The lamp unit 18 is rotated in the mounting direction with the lamp unit18 pushed against the radiating member 17. At this time, since the metalfoil 48 is provided on the surface of the heat conductive sheet 22 andthe metal foil 48 comes into contact with the contact surface 94 of theradiating member 17, the heat conductive sheet 22 can move easily andsmoothly with respect to the contact surface 94 of the radiating member17 in comparison with a case where the silicone sheet 47 is in directcontact with the contact surface 94 of the radiating member 17 forexample, so that the rotational operation of the lamp unit 18 can befacilitated. In addition, since the restricting portion 43 comes intoabutment with the contact surface 94 of the radiating member 17 torestrict further resilient deformation of the heat conductive sheet 22and hence increase in pushing force that pushes the heat conductivesheet 22 against the contact surface 94 of the radiating member 17 isrestricted, the heat conductive sheet 22 can move easily with respect tothe contact surface 94 of the radiating member 17, so that therotational operation of the lamp unit 18 can be facilitated.

When rotating the lamp unit 18, even if there is only a small spacewhich allows insertion of fingers between a peripheral surface of thelamp unit 18 and the inner surface of the fixture body 15, the lamp unit18 can easily be rotated by getting the fingers caught by the fingerplacing portions 70 projecting from the lower surface of the glove 26.If the fingers can be get caught by the glove 26, a plurality ofdepressed portions may be provided in the peripheral portion of theglove 26 instead of the finger placing portions 70.

By rotating the lamp unit 18 in the mounting direction, the respectivekeys 89 of the socket 16 enter and are caught by the lateral groove 44 bof the respective key grooves 44 of the base member 29 and therespective keys 45 of the base member 29 enter and are caught by thelateral grooves 88 b of the respective key grooves 88 of the socket 16,whereby the lamp unit 18 is mounted on the socket 16. The respectivelamp pins 67 of the lamp unit 18 move in the respective connectinggrooves 87 of the socket 16, and come to contact with and areelectrically connected to the respective terminals arranged on the uppersides of the respective connecting grooves 87.

When the lamp unit 18 is mounted, the upper surface of the base member29 of the lamp unit 18 comes into intimate contact with the contactsurface 94 of the radiating member 17 via the heat conductive sheet 22,so that efficient heat conduction from the lamp unit 18 to the radiatingmember 17 is achieved.

When demounting the lamp unit 18 from the lighting fixture 11, first ofall, the lamp unit 18 is rotated in the demounting direction, which is adirection opposite from the mounting direction, whereby the respectivekeys 89 of the socket 16 move to the vertical grooves 44 a of therespective key grooves 44 of the base member 29 and the respective keys45 of the base member 29 move to the vertical grooves 88 a of therespective key grooves 88 of the socket 16, so that the respective lamppins 67 move in the respective connecting grooves 87 of the respectivesocket 16 away from the respective terminals arranged on the upper sideof the respective connecting grooves 87. Subsequently, by moving thelamp unit 18 downward, the respective lamp pins 67 come apart from therespective connecting grooves 87 of the respective socket 16, thevertical grooves 44 a of the respective key grooves 44 of the basemember 29 come apart from the respective keys 89 of the socket 16 and,simultaneously, the respective keys 45 of the base member 29 come apartfrom the vertical grooves 88 a of the respective key grooves 88 of thesocket 16, and then the base member 29 comes apart from the insertionopening 86 of the socket 16, so that the lamp unit 18 can be demountedfrom the socket 16.

Subsequently, lighting of the lamp unit 18 will be described.

If electricity is supplied from a power supply line to the lightingcircuit 25 via the terminal base 97, the terminals of the socket 16, andthe lamp pins 67 of the lamp unit 18, lighting power is supplied fromthe lighting circuit 25 to the LED elements of the light-emitting module23, so that the LED elements is lit. Light radiated from thelight-emitting portion 52 by lighting of the LED elements travels in thelight guide portion 59 of the light control unit 24, passes through theglove 26, and is emitted from the opening on the lower surface of thefixture body 15.

When the LED elements are turned ON, heat that the LED elements of thelight-emitting module 23 generate is mainly conducted efficiently fromthe substrate 51 of the light-emitting module 23 to the heat conductingportion 40 of the base member 29 bonded thermally thereto via the heatconductive sheet 55, is conducted efficiently from the heat conductingportion 40 of the base member 29 to the radiating member 17 being inintimate contact thereto via the heat conductive sheet 22, and isradiated into air from the surface of the radiating member 17 includingthe plurality of the radiating fins 92.

Part of the heat conducted from the lamp unit 18 to the radiating member17 is conducted respectively to the fixture body 15, a plurality of themounting springs 96 and the mounting plate 99, and is radiated into airalso therefrom.

Heat that the lighting circuit 25 generates is conducted to the case 28and the glove 26, and radiated into air from the surfaces of the case 28and the glove 26.

According to the lamp unit 18 in this embodiment configured as describedabove, since the lighting circuit 25 is accommodated in the case 28 ofthe housing 21 and the light-emitting module 23 is mounted on the basemember 29 at the position above the position of the lighting circuit 25in the case 28, heat of the light-emitting module 23 can be conductedefficiently to the base member 29 and radiating performance from thebase member 29 is improved and, furthermore, owing to the arrangement ofthe light-emitting module 23, part of the base member 29 to which thelight-emitting module 23 is mounted does not have to projectsignificantly downward, so that increase in amount of material used forthe base member 29 and increase in mass of the base member 29 can beinhibited. In addition, with the structure of the lamp unit 18, a largelight shielding angle can be secured by the lamp unit 18 itself, andhence the lamp unit 18 having a narrow angle light distribution can beprovided.

Also, since the heat conducting portion 40 of the base member 29 wherethe light-emitting module 23 is mounted is formed to be thicker thanother portions of the base member 29, the heat capacity of the heatconducting portion 40 is large, and hence the heat of the light-emittingmodule 23 is efficiently conducted to the heat conducting portion 40,thereby improving the radiating performance.

Also, in the state in which the lamp unit 18 is mounted on the socket16, the keys 45 are caught by the socket 16, and the lamp unit 18 issupported by the keys 45. Since the thickness of the heat conductingportion 40 of the base member 29 is large, if the keys 45 are providedon an upper side of the base member 29 for example, an upper side of theheat conducting portion 40 in the thickness direction is supported bythe keys 45, and hence the distance from the positions of the keys 45 tothe lower surface of the heat conducting portion 40 is increased, sothat the moment is increased. In this embodiment, since the keys 45 areprovided at positions closer to a lower side with respect to theposition of the end surface 36 of the base member 29, that is, since thekeys 45 are provided at an intermediate position of the heat conductingportion 40 in the thickness direction, the moment can be reduced, andhence the support of the lamp unit 18 is stabilized.

Also, since the case 28 is formed of the resin material, improvement ofinsulating properties of the lighting circuit 25 is achieved.

In addition, since the light-emitting module 23 is arranged at the upperposition closer to the end surface 36 of the base member 29 with respectto the flat panel portion 31 of the case 28, the influence of heatgenerated by the light-emitting module 23 on the case 28 formed of theresin material can be alleviated.

Since the light-emitting module 23 and the lighting circuit 25 areseparated by the light control unit 24, the influence of the heatgenerated by the light-emitting module 23 on the lighting circuit 25 canbe alleviated, and the insulating properties between the light-emittingmodule 23 and the lighting circuit 25 can be improved.

By using the light control unit 24, light irradiated from thelight-emitting portion 52 of the light-emitting module 23 can be emittedfrom the glove 26 without being shielded by the light-emitting module 23or the like, so that lowering of light output can be prevented.

Since the lighting circuit board 64 formed with the opening 66 so as tooppose the light-emitting portion 52 of the light-emitting module 23 isused for the lighting circuit 25, the light radiated from thelight-emitting portion 52 of the light-emitting module 23 can beprevented from being shielded by the lighting circuit board 64.

Also, among the lighting circuit components 65 to be mounted on thelighting circuit board 64, at least one of large components having alarge projecting height from the lighting circuit board 64, heatgenerating components with high calorific value, and the componentshaving a low tolerance for heat is mounted at outer positions of thelighting circuit board 64. Therefore, such an event that the largecomponent shields light or the large component interferes with the lightcontrol unit 24 can be prevented, heat generated by the heat-generatingcomponents can easily be released to the peripheral surface portion 32of the case 28 to inhibit the temperature rise of the heat-generatingcomponents. In addition, by positioning the components having a lowtolerance for heat close to the peripheral surface portion 32 of thecase 28 at a low temperature, the temperature rise of the componentshaving a low tolerance for heat can be inhibited.

Also, since the light-emitting module 23 and the lighting circuit 25 areseparated by the light control unit 24, and the components having a lowtolerance for heat from among the lighting circuit components 65 aremounted at positions apart from the light control unit 24 on thelighting circuit board 64, the temperature rise of the components havinga low tolerance for heat can be inhibited.

Since the annular lighting circuit board 64 includes components whichmay generate a noise such as a switching element mounted at positionsaway and opposite from the position of the power supply input portion interms of the circumferential direction, noises from these components canbe prevented from riding on the power supply line.

Since the lighting circuit 25 is provided with the lamp pins 67 so as toextend upright therefrom to the lighting circuit board 64, the wiringstructure between the lighting circuit board 64 and the lamp pins 67 issimplified and, in addition, the lamp pins 67 can be built into thehousing 21 together with the lighting circuit board 64, wherebyassembleability is improved.

Since the base member 29 of the lamp unit 18 mounted on the socket 16 ofthe lighting fixture 11 comes into contact with and thermally connectedto the contact surface 94 of the radiating member 17 via the heatconductive sheet 22, heat of the light-emitting module 23 can beconducted efficiently to the radiating member 17, so that the radiatingperformance can be improved.

Furthermore, when mounting the base 30 of the lamp unit 18 by pressingthe same against the contact surface 94 of the radiating member 17 viathe heat conductive sheet 22, the heat conductive sheet 22 comes intoabutment with the contact surface 94 of the radiating member 17 and isresiliently deformed, and then is pressed against the interior of thedepressed portion first. Then, the base 30 (that is, the restrictingportion 43) comes into abutment with the contact surface 94 of theradiating member 17 and restricts further resilient deformation of theheat conductive sheet 22, so that the pressing force that the heatconductive sheet 22 is pressed against the contact surface 94 of theradiating member 17 is restricted from increasing. Therefore, the heatconductive sheet 22 can easily move with respect to the contact surface94 of the radiating member 17, and the rotational operation of the lampunit 18 is easily achieved and, in addition, excessive deformation ofthe heat conductive sheet 22 is prevented and damage of the heatconductive sheet 22 can be prevented.

In addition, since the metal foil 48 is provided on the surface of theheat conductive sheet 22, the heat conductive sheet 22 can move easilyand smoothly with respect to the contact surface 94 of the radiatingmember 17 in comparison with the case where the silicone sheet 47 is indirect contact with the contact surface 94 of the radiating member 17for example, so that the rotational operation of the lamp unit 18 can befacilitated. In addition, at the time of rotational operation of thelamp unit 18, the heat conductive sheet 22 can be prevented fromseparating from the base member 29 due to a frictional force withrespect to the contact surface 94 of the radiating member 17.

Also, when mounting the base 30 of the lamp unit 18 by pressing the sameagainst the lighting fixture 11 (the radiating member 17) side via theheat conductive sheet 22, the heat conductive sheet 22 comes intoabutment with the lighting fixture 11 and is resiliently deformed, andthen is pressed against the interior of the depressed portion 30 afirst. Then, the base 30 (the restricting portion 43) comes intoabutment with the lighting fixture 11 side and restricts furtherresilient deformation of the heat conductive sheet 22, therebyrestricting increase of the pressing force that the heat conductivesheet 22 is pressed against the lighting fixture 11 side. Therefore,excessive deformation of the heat conductive sheet 22 is prevented, themounting operation on the basis of the rotation of the lamp unit 18 withrespect to the lighting fixture 11 is facilitated, and damage of theheat conductive sheet 22 can be prevented.

In addition, since the restricting portion 43 is formed in theperipheral portion of the end surface 36, a peripheral portion of theheat conductive sheet 22 arranged in the depressed portion 30 a can bepositioned.

FIG. 8 and FIG. 9 show a second embodiment. The same configurations asin the first embodiment are designated by the same reference numeralsand description thereof is omitted.

The restricting portion 43 formed so as to project from the end surface36 of the base member 29 includes a central restricting portion 43 aformed so as to project in a circular shape at a center of the basemember 29 and a peripheral restricting portion 43 b formed so as toproject in an annular shape in a peripheral portion of the base member29. The central restricting portion 43 a and the peripheral restrictingportion 43 b are lower than the projecting dimension of the heatconductive sheet 22 from the end surface 36 of the base member 29 if thelamp unit 18 is not mounted on the lighting fixture 11 and no pressureis applied on the heat conductive sheet 22 and, in addition, aprojecting height h1 of the central restricting portion 43 a from theend surface 36 of the base member 29 is higher than a projecting heighth2 of the peripheral restricting portion 43 b. A depressed portion 101shallower than the thickness of the heat conductive sheet 22 is formedin the end surface 36 of the base member 29.

The heat conductive sheet 22 is formed into an annular shape so as to bemounted in a depressed portion between the central restricting portion43 a and the peripheral restricting portion 43 b.

Then, when mounting the base member 29 of the lamp unit 18 by pressingthe same against the contact surface 94 of the radiating member 17 viathe heat conductive sheet 22, the heat conductive sheet 22 isresiliently deformed by coming into abutment with the contact surface 94of the radiating member 17, and then the central restricting portion 43a comes into abutment with the contact surface 94 of the radiatingmember 17, whereby further resilient deformation of the heat conductivesheet 22 is restricted. If the lamp unit 18 is rotated in the mountingdirection with the central restricting portion 43 a in abutment with thecontact surface 94 of the radiating member 17, the surface area of thecontact surface 94 of the radiating member 17 where the centralrestricting portion 43 a is in contact therewith is small, and theoperator operates the peripheral portion of the case 28 or the glove 26apart from the central restricting portion 43 a radially outward byholding with his or her hand, the lamp unit 18 can be rotated with alight force.

The peripheral restricting portion 43 b restricts the position of theheat conductive sheet 22 or, if the base member 29 of the lamp unit 18is obliquely pressed against the contact surface 94 of the radiatingmember 17, the peripheral restricting portion 43 b comes into abutmentwith the contact surface 94 of the radiating member 17 and restricts theresilient deformation of the heat conductive sheet 22.

The peripheral restricting portion 43 b is not limited to have anannular shape, and may be formed discontinuously by being partlynotched, or may be projections provided at a plurality of positions suchas three, four, or five positions.

FIG. 10 shows a third embodiment. The same configurations as in thefirst embodiment are designated by the same reference numerals anddescription thereof is omitted.

A plurality of the finger placing portions 70 of the glove 26 may beformed into an elongated rib shape projecting from the surface of theglove 26 along the radial direction of the glove 26 instead of theplurality of projections in the embodiment describe above. The ribformed areas are included in areas opposing the cover portion 60 of thelight control unit 24, and little affects the light distribution.

Then, by forming the plurality of the rib-shaped finger placing portions70 on the glove 26, when mounting and demounting the lamp unit 18 withrespect to the lighting fixture 11, the fingers can easily be caught bythe plurality of the rib-shaped finger placing portions 70, so that therotational operation of the lamp unit 18 can easily be performed.

In the embodiments described above, by forming the case 28 of metal andbringing the lighting circuit 25 into thermally contact with the case 28by the heat conductive resin such as silicone resin, the temperaturerise of the lighting circuit 25 may be inhibited by causing the heat ofthe lighting circuit 25 to be efficiently conducted and radiated to thecase 28.

In addition, in the respective embodiments, the case 28 of the housing21 and the base member 29 may be formed integrally of metal or resinsuperior in heat conductivity.

FIG. 11 shows a fourth embodiment. The same configurations as in theabove-described embodiment are designated by the same reference numeralsand description thereof is omitted.

The heat conductive sheet 22, the depressed portion 30 a, and therestricting portion 43 are provided on the contact surface 94 of theradiating member 17.

The restricting portion 43 may include both of the central restrictingportion 43 a and the peripheral restricting portion 43 b as shown in thedrawing or, alternatively, only one of the central restricting portion43 a and the peripheral restricting portion 43 b may be provided.

In this case, the end surface 36 of the lamp unit 18 is provided in aflat shape.

Alternatively, either one of the heat conductive sheet 22 and therestricting portion 43 (the depressed portion 30 a) may be provided onthe base member 29 of the lamp unit 18, and the other one of those maybe provided on the radiating member 17. In addition, if the heatconductive sheet 22 is provided on the radiating member 17 side and ifthe heat conductive sheet 22 is provided with the metal foil 48, themetal foil 48 may be provided on the lamp side. Alternatively, if theheat conductive sheet 22 is provided on the lamp side and if the heatconductive sheet 22 is provided with the metal foil 48, the metal foil48 may be provided on the radiating member 17 side. What is essential isthat the heat conductive sheet 22 is interposed between the base 30 ofthe lamp unit 18 and the radiating member 17.

Since the heat conductive sheet 22 is interposed between the base 30 ofthe lamp unit 18 mounted on the socket 16 of the lighting fixture 11 andthe radiating member 17 and is thermally joined, the heat of thelight-emitting module 23 can be conducted efficiently to the radiatingmember 17, so that the radiating performance can be improved. Whenmounting the base 30 of the lamp unit 18 by pressing the same againstthe contact surface 94 of the radiating member 17 via the heatconductive sheet 22, the heat conductive sheet 22 is interposed betweenthe base 30 and the radiating member 17 and is resiliently deformed.Since the restricting portion 43 is interposed between the base 30 andthe radiating member 17, further resilient deformation of the heatconductive sheet 22 is restricted, and the pressing force that the heatconductive sheet 22 is pressed against the base 30 or the radiatingmember 17 is restricted from increasing, the rotational operation of thelamp unit 18 can be facilitated even if the heat conductive sheet 22 isinterposed and, in addition, excessive deformation of the heatconductive sheet 22 is prevented, so that the damage of the heatconductive sheet 22 can be prevented.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto, cover such forms or modifications as would fall within the scope andspirit of the inventions.

1. A lamp unit comprising: a light-emitting module having asemiconductor light-emitting element; a housing having a case opening inthe direction of irradiation of light and a base on the case on a sideopposite from the direction of irradiation of the light, thelight-emitting module mounted on the base, a base surface formed on anouter surface of the base on the opposite side from the case side, and adepressed portion formed on the base surface; a lighting circuitaccommodated in the housing; and a resiliently deformable heatconductive sheet disposed in the depressed portion.
 2. A lamp unitcomprising: a light-emitting module having a semiconductorlight-emitting element; a housing having a case opening in the directionof irradiation of light and a base on the case on a side opposite fromthe direction of irradiation of the light, the light-emitting modulemounted on the base, and a base surface formed on an outer surface ofthe base on the opposite side from the case side; a lighting circuitaccommodated in the housing; a resiliently deformable heat conductivesheet disposed on the base surface; and a restricting portion providedon the base surface, having a projecting height from the base surfacelower than the heat conductive sheet which is not resiliently deformed,and configured to restrict the resilient deformation of the heatconductive sheet by an abutment with the lighting fixture side whenmounted on the lighting fixture.
 3. The unit according to claim 2,wherein the restricting portion projects from a center portion of thebase surface.
 4. The unit according to claim 2, wherein the restrictingportion projects from a peripheral portion of the base surface.
 5. Theunit according to claim 2, wherein the restricting portion projectsrespectively from the center portion and the peripheral portion of thebase surface.
 6. The unit according to claim 2, wherein the heatconductive sheet includes a silicone sheet and a metal foil, and thesilicone sheet is bonded to the base surface.
 7. A lighting fixturecomprising: the lamp unit according to claim 2; a socket on which thebase is mounted; and a radiating member which allows thermal contact ofthe base mounted on the socket thereto.
 8. The fixture comprising: alamp unit having a light-emitting module having a semiconductorlight-emitting element, a case opening in the direction of irradiationof light, a base on the case on a side opposite from the direction ofirradiation of the light, a housing in which the light-emitting moduleis mounted on the base, and a lighting circuit accommodated in thehousing; a socket on which the base is mounted; a radiating member whichallows thermal contact of the base mounted on the socket thereto; aresiliently deformable heat conductive sheet interposed between the baseand the radiating member; and a restricting portion provided on at leastone of the base and the radiating member, having a projecting heightfrom the base or the radiating member lower than the projecting heightthereof from the base and the radiating member where the heat conductivesheet which is not resiliently deformed is disposed, and configured torestrict the resilient deformation of the heat conductive sheet when thebase is mounted on the socket.